A method to correct differential nonlinearities in subranging analog-to-digital converters used for digital gamma-ray spectroscopy

The influence on $\gamma$-ray spectra of differential nonlinearities (DNL) in subranging, pipelined analog-to-digital converts (ADCs) used for digital $\gamma$-ray spectroscopy was investigated. The influence of the DNL error on the $\gamma$-ray spectra, depending on the input count-rate and the dynamic range has been investigated systematically. It turned out, that the DNL becomes more significant in $\gamma$-ray spectra with larger dynamic range of the spectroscopy system. An event-by-event offline correction algorithm was developed and tested extensively. This correction algorithm works especially well for high dynamic ranges

Drosophila olfactory receptors as classifiers for volatiles from disparate real world applications

Olfactory receptors evolved to provide animals with ecologically and behaviourally relevant information. The resulting extreme sensitivity and discrimination has proven useful to humans, who have therefore co-opted some animals' sense of smell. One aim of machine olfaction research is to replace the use of animal noses and one avenue of such research aims to incorporate olfactory receptors into artificial noses. Here, we investigate how well the olfactory receptors of the fruit fly, Drosophila melanogaster, perform in classifying volatile odourants that they would not normally encounter. We collected a large number of in vivo recordings from individual Drosophila olfactory receptor neurons in response to an ecologically relevant set of 36 chemicals related to wine ('wine set') and an ecologically irrelevant set of 35 chemicals related to chemical hazards ('industrial set'), each chemical at a single concentration. Resampled response sets were used to classify the chemicals against all others within each set, using a standard linear support vector machine classifier and a wrapper approach. Drosophila receptors appear highly capable of distinguishing chemicals that they have not evolved to process. In contrast to previous work with metal oxide sensors, Drosophila receptors achieved the best recognition accuracy if the outputs of all 20 receptor types were used

Flow Equations for N Point Functions and Bound States

We discuss the exact renormalization group or flow equation for the effective action and its decomposition into one particle irreducible N point functions. With the help of a truncated flow equation for the four point function we study the bound state problem for scalar fields. A combination of analytic and numerical methods is proposed, which is applied to the Wick-Cutkosky model and a QCD-motivated interaction. We present results for the bound state masses and the Bethe-Salpeter wave function. (Figs. 1-4 attached as separate uuencoded post-script files.)Comment: 17 pages, HD-THEP-93-3

The Indian Ocean tsunami: socio-economic impacts in Thailand

On the morning of 26 December 2004 large areas of coastal southern Thailand were transformed when a tsunami, generated by a powerful submarine earthquake in the Indian Ocean, swept ashore. Officially, there were 5395 confirmed deaths in Thailand with another 2932 people listed as missing. In February 2005 a team led by Dr Ben Horton of the University of Pennsylvania was awarded an SGER grant by the National Science Foundation to undertake exploratory research on the tsunami in Malaysia and Thailand. This report summarizes the preliminary conclusions of the social science element of the Thai fieldwork. The team undertook fieldwork in three main sites during July 2005: Koh Lanta, Koh Phi Phi and Khao Lak. We chose Koh Phi Phi as a small, tourist (backpacker)-oriented island economy with high levels of damage and casualties; Koh Lanta as a site with a significant population of fisherfolk with a long presence in the area; and Khao Lak as a mainland site with the highest number of casualties in Thailand and with a mixed tourism-fishing economy

Clustering, Order, and Collapse in a Driven Granular Monolayer

Steady state dynamics of clustering, long range order, and inelastic collapse are experimentally observed in vertically shaken granular monolayers. At large vibration amplitudes, particle correlations show only short range order like equilibrium 2D hard sphere gases. Lowering the amplitude "cools" the system, resulting in a dramatic increase in correlations leading either to clustering or an ordered state. Further cooling forms a collapse: a condensate of motionless balls co-existing with a less dense gas. Measured velocity distributions are non-Gaussian, showing nearly exponential tails.Comment: 9 pages of text in Revtex, 5 figures; references added, minor modifications Paper accepted to Phys Rev Letters. Tentatively scheduled for Nov. 9, 199

Evolution Equations for the Quark-Meson Transition

Evolution equations describe the effect of consecutively integrating out all quantum fluctuations with momenta larger than some infrared cutoff scale k. We develop a formalism for the introduction of collective degrees of freedom at some intermediate scale and derive the corresponding evolution equations. This allows to account for the appearance of bound states at some characteristic length scale as, for example, the mesons in QCD. The vacuum properties, including condensates of composite operators, can be directly infered from the effective action for k->0. We compute in a simple QCD-motivated model with four-quark interactions the chiral condensate \bar\psi\psi and the effective action for pions including f_\pi. A full treatment of QCD along these lines seems feasible but still requires substantial work. (5 figures available by ordinary mail upon request)Comment: 31 pages, HD-THEP-94-

Asymmetric Organocatalysis and Continuous Chemistry for an Efficient and Cost-Competitive Process to Pregabalin

Herein, we present the scale up development of an innovative synthetic process to pregabalin. The process is underpinned by two enabling technologies critical to its success; continuous chemistry allowed a safe and clean production of nitroalkene, and asymmetric organocatalysis gave access to the chiral intermediate in an enantioenriched form. Crucial to the success of the process was the careful development of a continuous process to nitroalkene and optimization of the organocatalyst and of the reaction conditions to attain remarkably high turn-over frequency in the catalytic asymmetric reaction. Successful recycle of the organocatalysts was also developed in order to achieve a cost-competitive process

The beta functions of a scalar theory coupled to gravity

We study a scalar field theory coupled to gravity on a flat background, below Planck's energy. Einstein's theory is treated as an effective field theory. Within the context of Wilson's renormalization group, we compute gravitational corrections to the beta functions and the anomalous dimension of the scalar field, taking into account threshold effects.Comment: 13 pages, plainTe

Note: a dual temperature closed loop batch reactor for determining the partitioning of trace gases within CO2-water systems

An experimental approach is presented which can be used to determine partitioning of trace gases within CO2-water systems. The key advantages of this system are (1) The system can be isolated with no external exchange, making it ideal for experiments with conservative tracers. (2) Both phases can be sampled concurrently to give an accurate composition at each phase at any given time. (3) Use of a lower temperature flow loop outside of the reactor removes contamination and facilitates sampling. (4) Rapid equilibration at given pressure/temperature conditions is significantly aided by stirring and circulating the water phase using a magnetic stirrer and high-pressureliquid chromatography pump, respectively